In-situ DC and wave electric fields were detected above and within a sporadic-E layer by sounding rocket-borne instruments in the presence of quasi-periodic backscatter radar echoes. When analyzed in conjunction with plasma density measurements, the in-situ data reveal complex electrodynamics associated with the sporadic-E layer. The electric field data show: (1) a sinusoidal variation of ¿3 mV/m between 130--170 km which may be associated with a gravity wave with a horizontal wavelength of ~20 km; (2) localized DC electric fields of ~20 mV/m associated with narrow (few km) plasma density depletions near 125 km altitude; and (3) a broad spectrum of plasma irregularities, including long wavelength (km-scale) and meter-scale waves. No short-scale plasma waves were observed in-situ above 115 km, despite the fact that simultaneous radar data show echoes originating from altitudes as high as 135 km. ¿ 1998 American Geophysical Union